Waterbed mattress cornerpiece



FIG. 1 is a front elevational view of a waterbed mattress cornerpiece showing my new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a side elevational view thereof, the opposite side being a mirror image of that shown;

FIG. 4 is a top plan view thereof, the bottom being a mirror image of that shown;

FIG. 5 is a vertical cross-sectional view thereof, taken along line 5--5 of FIG. 1;

FIG. 6 is a horizontal cross-sectional view thereof, taken along line 6--6 of FIG. 1; and

FIG. 7 is a top, front, and side perspective view thereof, the broken-line depiction of a portion of the mattress and indicia being for illustrative purposes only and forming no part of the claimed design. 

The ornamental design for a waterbed mattress cornerpiece, as shown and described. 